Heretofore, it is known that a stereovision can be obtained through the use of parallax by displaying two images of right-eye and left-eye images in combination. Such a stereoscopically viewable image (hereinafter, stereoscopic image or stereo image) is generated based on a plurality of images having a parallax obtained by imaging the same subject from different directions.
The generation of such stereoscopic images is performed not only in the fields of digital cameras and televisions but also in the field of radiological image capturing. That is, it is practiced that a plurality of radiological images having a parallax is obtained by applying radiation to a subject from different directions and detecting radiation transmitted through the subject with respect to each direction using a radiological image detector, and a stereoscopic image is generated based on these radiological images. The generation of the stereoscopic image in the manner described above allows a radiological image having a sense of depth to be observed, that is, it is possible to observe a radiological image more suitable for diagnosis as described, for example, Japanese Unexamined Patent Publication No. 2010-110571.